Sorry. I cannot agree.
Each satoshi carries an history. And it is trivial to verify it: Identifying ang tracking any unit of satoshi can be done with ease: this makes bitcoin non fungible.
It is fungible, any thing, when it is not possible to tell apart an item from another of the same species.
One can taint and track a gold bar, for example. But "gold", the substance, is fungible ... even though a gold bar may not be fungible (due to eventual marks, numbers, registres, etc), it is enough to melt it, and form a new bar ( the atoms are not easily discernable from each other).
Mixers (coinjoin) seem to be, for Bitcoin, what melting is to a gold bar, IMHO.